Microfilm projector



Ju1y16,1946. R PLACE I 2,404,189

' MICR'QFILM PROJECTOR Filed sept. 24, 1942 3 sheets-sheet l;

' Q mi" LN www.

July 16, 1946. R PLACE 2,404,189

MICROFILM PROJECTOR Filed Sept. v24, 1942 3 Sheets-Sheet 3 gmc/MM oer P50/0C,

Patented July 16, 1946v Robert Place, Waltham,

Mass., Y assignor to Graphic Microfilm Service, Inc., Waltham, Mass., a corporation of Massachusetts Application september 24, 1942, seriaiNo. 459,565

(o1. ssi-24) 6 Claims.

This invention relates toimprovements in microfilm projectors or reading machines. While the improvements of the present invention are applicable to any type of projector they are particularly adapted for use in connection with and Will be herein described as embodied in adirect projection machine. Y

An object of the invention is to provide an electrically driven machine extremely simple in construction and characterized by the utmost ease in manipulation. i'

Another object is to provide a projection device wherein tearing or other damage to the film is minimized and in this regard the invention specifically contemplates the provision of means to delay closing of the lm gate until rotation of the armature ceases following deenergization of the film drive motor. f

It is a further object of .the invention to provide a projection device capable of imparting various magnications to the projected image and which may be readily operated to scan or enlarge any desired part of the projected image.

Other objects and advantages will be apparent from the following description taken in conjunction with the accompanying drawings wherein a preferred embodiment of the invention has been selected for exemplification. I.

In the drawings:

Fig. 1 is a side elevational view of a reading machine cabinet according to the present invention;

Fig. 2 is a front elevational view of the device of Fig. 1;

Fig. 3 is a plan view of the projector apparatus;

Fig., 4 is a side elevational view of Fig. 3; y

Fig. 5 is a plan View of the sliding lens structure; and A q Figs. 6 and '7 are front and rear views respectively of a circuit breaker associated with the electric motor. g Y y l Referring more particularly to the drawlngs lwherein like numerals refer to like parts, the

reading machine of Figs. 1 and 2 is composed of projector apparatus indicated in its entirety at A, and a shadow box B suitably supported by legs or the like C.

The projector apparatus A is driven by a reversible electric motor 2 driving a worm 4 meshing with a worm gear drive 6 which in turn drives a cross drive shaft I0 suitably supported for reciprocal movement. The drive to shaft YI0 is through a sleeve 8 directly attached to worm gear 6 and diagonally slotted as at I 4 to receive apin I2 carried by the shaft I0. lBevel gears. I6 55 *purposen is a centrifugal circuit breaker as .bestel volves the pin I2 will be urged to one extremity` or the other of the diagonal slot I4, thus to force shaft I2 to. slide 'its full length of movement in one direction to mesh one set of bevel gears I6 and I8 and disengage the other set and reversel drive of worm gear 6 from the motor 2 will urge4 the pin vI2 to the opposite extremity of the diagonal slot I4 thus sliding shaft I0 so that the' other set of bevel .gears I6 and I8 will operatively mesh and the first set will be disengaged. A brak-l ing assembly indicated at 20 is provided to retard the action of shaft I0 forcing it to slide back and forth. I l .g

Spindles 22 are preferably indirectly connect` ed to bevel gears I8 by the medium of ratchets 24 attachedvdirectly to gears I8 by a sleeve 2,5. Cooperating With ratchets 24 are 'spring held pawls 28 supported by flanges 26 which are xed to spindles 22 in such a manner that overrunning of the spindles 22 is permitted to facilitate loading of theV projector while one pair of gears` I6 and I8 is engaged.

The film carried by the film reel 'supported the spindles 22 passes under rollers 30 and between a pair of glass pressure plates, the upper one being designated at 32 and secured in position on a plate hereinafter referred to and designated by the numeral 44. A suitable boss 34 carried by said plate is of the proper height to fixedly position the lower surface of the plate 32 in the focal plane of the objective lensof the projector. 'Ihe plate 32 is secured on the base 34 byv means of screws 36. The lower glass 40 is supported directly below the plate 32 in a movable frame 35 fulcrumed at 38 and actuated by a solenoid` 42. The solenoid 42 is connected through reversible motor 2 to a common control as will vhereinafter appear and the arrangement is such that the glass plates 32 and 40 are separated at all times while the film is moved between them. Y

Since the armature of electric motor 2 will continue to rotate a short while after deenergization of .the motor, it has been found advisable Y to appropriately delay deenergization of the film gate actuating solenoid 42 until such rotation lceases and the lm comes substantially to rest to prevent tearing or scratching ofthe lmas would result from abruptly clamping a moving film in the gate. A suitable mechanism for this 1 shown in Figs. 6 and'l. Herein a disc H4 of non-conducting material is keyed to rotate withv the motor shaft and carries on its front or outer face concentric conductor rings I l and I l2 which conduct current through brushes H8 to the lm gate actuating solenoid 42. Pivotally mounted on pin |28 extendingY from ring H2 .to the rear or innerface of disc lil 14 isa dog I-If-8 held :against pin abutment '|28 by aweak spring 122. The relative. strength of spring |22 and weight of dog H8 is such that any rotation of the'moto'r shaft and disc H4 causes the dog to swing outwardly into engagement with contact |24 to complete the circuit to solenoid 112 whereby 'the solenoid is energized and the vfilm gate pressure if' plates remain open so long as the motor sha-Tt rotates irrespective of the moment :o'f deenergization of the motor.

The film supporting and advancing mechanism and glass plate construction above described and as shown in Fig. `f3 are mounted on disc .44 which revolves '360 von the support of vrollers '46 prefeerably V:four in Anumber and "which may berrotated by akno'b tor Lthe like v545. Rollersll are -xedly mounted on 1a panel 48' `which is vamounted as hereinafterdescri-bed on the main support frame i) of Lthe shadow box l 'so that l the 'image fon the filmmayfbe rotated'in ainy'pos'itionfor'may be skimmed so as to ibring any 'portion of thelm y Y frame to the center-of the reading screen.

'The means by which `*variable magriication is preferably Iaccomplished is best; shown l'in Fig. 5` wherein lenses =52 V'and i54 bidh-*ferent focal lengths are v`carried by sliding lens lmounts 51S supported iin blockrl58- Small gear racks lare I attached A:to th'eslidable 4lens rnountsBB -andien` Y gage a pinion 82 xed to Worm gear 64.y Gear 64 is driven by an 1engaging worm '65 car-Died 'lby a vsliidable yand vrotatable control` shaft 188 which extends through v:the cabinet housing '-B and has a -knob or handle 18 keyed to the projecting end ith-eredi".Y '-Block '158 is slidably-supported channel 212 -carriedby the xed plate 558 and abut-rln'ents 14 are provided to limi-t the AsIiding movement fof Vthe 'block A'in the iclianfn'els. i

It will .be apparent that by-pulI-inlgor ipushing control knob 18 1and axially moving shaft 68,

` the block v58 will be shifted to locate either 'flens 521er -523 `in the -opticalf-pathto give ama'glnica'tion lin accordance with the fo'cal length of the lens selected and that by turning the iikn'ob 't8 toV Arotate #shaft 68 land the gear train fconnecti-ng with llens Vmounts 56, fthe selected lens may I.be positioned lfor lafcritic'al ffocus.

As -bes't illustrated -in Fig. 4, the lamp house 16 4and `condenser system 18 are supported lby lig-htingfelc'iencyican be provided for the dif-- ferent lenses.-

A wire bound flexible cable 84 Ais preferably provided Lfor l'furnishing the conductor support for the power v-li-nes to ythe motor 2 Yand solenoid f4 2 which, as explained above, are carried Aby 'plate This conSt-ruclll thereof projected to the center of the viewing screen through the medium of panel 48 carrying the rollers 46 engaging spaced portions of the plate periphery. Panel t8 carries rollers 90 and is in turn supported by engagement of the rollers in slots provided in a frame 85. Opposed edges of `frame 86 are slidably supported by rollers -8i! carried vby iixed'fpanel 5.0 which'forms the top o'f the shadow box. lThe arrangement is such that panel 48 is movable with frame 85 in one direction and movable relative to frame 88 in ia transverse direction of the same plane thus to shift disc 44 and the image producing means supported thereon into any desired planar position.

'Asa control means for the above, a block `2-'12 carriedr by ;mov.able panel 48 extends through a slot Vin xed plate 58 toprovide a socket for rod '19:4 which is universally swiveled through a swivel assembly indicated at 96 bracketed as at 98 to the inner wal-110i the shadow 4box B. "-Ilhe rod 94 extendsvdownwardly terminating near the reading screen |08 tobe readily accessible to the reader yor user "of the device .for skimming any portion of the image frame =to the center of the screen. y

Main control switch 184 is conveniently -p'o's'itionedon the `(floor of the `shadow box .in front of the lscreen l'', the control switch fof lcourse connecting with the conductors passi-ng Vtlhroiugh the flexible cable 84 and furnishing current to the lelectric motor 2 and '-sol'e'ndidflm whereby to substantially simultaneously J'a'c'tuate"the sam-'e so that the glass plates 132 .and 1'40 will be opened when 'the '-lm is advanced.

In the projection assembly shown in Figs. l Zand 2 it will be apparent tlfiat the screen p F110 @is mounted at a tilted angle parallel to the 'iixed lplaftea upon Iwhich the vprotectionapparait-us vis mounted for-direct projection but it will beunderstood any other suitable -direct or indirect lirejection 1airrangement mayibe y.employed if desired. .Itis apu,

parent a-lsotha-tl the forward part of the floor of the shadowbox B, 'is indicatedfat Il Ufmay v conveniently 'be employed `"as a writing shelf..

means, solenoid :means including a magnetically The supporting plate '44 maybe shifted in order actuated member operatively connected to at least one of 'sa-id plates. fan electric circuit between said motor and a source of current, and a second cir-1 cuit between said solenoid fand saiidlsourca l'said last circuit *including Jcirciiit closing means `driven by said motor, Lsaid A"circuit closing means being normally open when said motor is at rest and' adapted to close instantly when movediin either direction, thereby holding said gate lopen fIiu-rin'g the time said lm is in motion, and closing iton'lly whilethe nlm is vat rest. Y Y f '2. In -a reading machine `in combination, supporti-ng Vand advancing means,v projection mechanism, La -l-m `gate "formed ofY separable plates, centrii-ugally -controlled contact means', an electric motor directly connected to said-'contact means 'andl connected "tor said lm advancing means 4through reversible reduction gearingelectro-magnetic means includ-ing a movable Pmem'fbcr nected Vto said source, said Lelectro--maigneti-c "means, and said centrifuga/ily controlled contact 3. In a reading machine in combination, film supporting and advancing means, projection mechanism, a lm gate formed of a pair of plates in contact with each other, one of said plates being movable, an electric motor connected to reversible reduction gearing for driving said advancing means in either direction, centrifugally controlled contact means carried directly on the rotor of said motor, electro-magnetic means including a movable member operatively connected to said movable plate, an electric circuit between said motor and a source of current, and a second circuit connected to said source, said electromagnetic means and to said centifugally controlled contact means, said last circuit being normally open when said motor is at rest, and adapted to close instantly when said motor is energized, thereby energizing said magnetic means and holding said. gate open, and adapted to continue to energize said magnetic means after said motor is deprived of current and decelerates substantially to a stop.

4. In a reading machine in combination, fllm supporting and advancing means, projection mechanism, a iilm gate formed of a stationary plate, and a pivoted movable plate in contact therewith, an electric motor for driving said advancing means in either direction through reversible reduction gearing, normally open een trifugally controlled contact means carried on the rotor of said motor and adapted to close substantially instantly when said rotor starts moving, a solenoid having a movable member operatively connected to said pivoted plate, an electric circuit between said motor and source of current, a second circuit connected to said source and including said solenoid and said centrifugally controlled contact means, said second circuit being adapted to close and thereby open said film gate as current is supplied to said motor and it starts rotating, said second circuit being adapted to continue to receive energy after said motor is deenergizedv and until said rotor comes to rest, thereby eecting the closure of said film gate only while said` motor is at rest.

5. In a reading machine in combination, a cabinet, film handling and projection mechanism positioned at the top of the cabinet, a viewing screen positioned in the lower portion of said cabinet, and having its mid portion cut by the optical axis of said projection mechanism, a rectangular frame at right angles to and cutting said optical axis and adapted to be positively stopped at two positions spaced apart from each other, a pair of lenses mounted in said frame in spaced relation to each other one of them being in alignment with the optical axis when said frame is in one position and the other being adapted to be brought into alignment with the optical axis when said frame is in the other position, and a shaft operable from the exterior of the cabinet and connected to said frame, said shaft being movable axially to position said lenses as aforesaid and rotatable to focally adjust a selected lens with respect to said projection mechanism.

6. In a reading machine in combination, iilm supporting and advancing means, projection mechanism, a film gate formed of a rigidly supported plate and a pivoted plate cooperating therewith, an electric motor connected to said film advancing means through reduction gearing and adapted to drive said advancing means in either direction, centrifugally controlled contact means including a rotary member on the arma-T ture of said motor, collector rings on said armature, and stationary brushes on the; frame of said motor, a solenoid having a movable member operatively connected to said pivoted plate for moving it out of contact with said stationary plate While said solenoid is energized, the ratio of said reduction gear furnishing the time delay between the opening of said gate and the movement of said film, a circuit between said"` motor. and a source of current, and a second circuit connecting said source to said centrifugally controlled contact means and said solenoid.

ROBERT PLACE. 

